I don’t think human psychology will allow a united approach to global warming. Too man people are too stupid, to egoistic or just in such a tight spot they can not afford being “climate-friendly”.
So I wonder if there are Mega-Projects available to stop global warming?
Some coming to mind:
Reflector mirror at Lagrange1 between Sun and Earth - even a 1.000.000km² mirror from ultrathin film would weigh 1000 tonnes at most.
Giant Air Scrubers and I mean giant. They would dwarf the pyramids and remove pullutants and CO² from the athmosphere.
In addition I think a originator principle should become common: Any nation not really trying to act clean should simply be burdened with massive tariff measures. Using modern technology it shouldn’t be too hard to find nations who polute the ocean unnececerrally.
Edit, it became reality:
Instead of treating the symptoms we must address the cause. The cause is CO2 emissions. The solution is to reduce these emissions. Keep the oil in ground as much as possible—we still need some for lubricants, solvents, polymers etc but honestly, burning oil is stupid since it can be used in much better ways. Although we must also reduce the use of single-use plastics, volatile organic compounds and “forever chemicals” as much as possible since these pose real environmental and health risks, too.
We have the technology to address the emissions—photovoltaics, wind, hydro and, yes, nuclear power; everyone can reduce or even stop meat consumption if they want; every city and country can build good public transport and walkable communities; every government can regulate harmful chemicals. The problem is societal inertia, NIMBY-ism, FUD plus outright conspiracy delusions and unwillingness to change from the powers-taht-be.
I believe that the more tolerable climate predictions assume that not only will we cut emissions but that we will also find a way to remove significant amounts of CO2 from the atmosphere.
So you are both right.